Given the expression
(12m+1) - (5m - 4)
First we need to expand the parenthesis
12m + 1 - 5m - (-4)
Note that product of two negative sign will result in a positive sign, so the expression becomes;
12m+1-5m+4
Collect like terms;
12m-5m+1+4
Evaluate the resulting expression:
12m-5m+1+4
7m + 5
Hence option C is correct